The present invention relates to a lamp with a reflector used in optical equipment or the like and to a method of manufacturing the same.
Conventionally, a lamp with a reflector having a configuration as shown in FIG. 11 has been known. In FIG. 11, numeral 1 indicates a high-pressure mercury lamp having a light-emitting portion 1a with a pair of electrodes 4 and sealing portions 1b and 1c provided in continuation of the respective ends of the light-emitting portion 1a. A metal base 2 provided with a threaded portion 2a at one end is fixed to the sealing portion 1b with an adhesive 22a such as cement or the like. Numeral 40 indicates a reflector. The reflector 40 has an opening portion 6, a reflecting surface 7 that is a paraboloid or an ellipsoid, and a hole 39. The sealing portion 1b of the lamp 1 is inserted into the hole 39 and the lamp 1 and the reflector 40 are combined into one component using the adhesive 22b. 
One electrode 4 is connected to the base 2. To the other electrode 4, a lead wire 5b is connected by welding. A front glass 9 is fixed to the opening portion 6 of the reflector 40 by a fixing clamp 10.
In turning on this lamp, a lead wire 5a connected to a power supply (not shown in the figure) is connected to the threaded portion 2a of the base 2 by thread fastening of a nut 2b and a lead wire 5b is connected to a power supply (not shown in the Figure).
In such a lamp with a reflector, a method of fixing the lamp 1 to the reflector 40 has been as follows. After the insertion of the sealing portion 1b into the hole 39, the hole 39 is filled with the adhesive 22b and then the position of the lamp 1 is adjusted so that the lamp is positioned at the focal point of the reflector 40. After that, the adhesive 22b is dried to fix the lamp 1 inside the reflector 40. Then, the front glass 9 is fixed to the opening portion 6. In this connection, the step of adjusting the position of the lamp 1 is carried out with the lamp 1 being oriented horizontally and being turned on (hereinafter this state of the lamp 1 is referred to as a xe2x80x9chorizontal turn-on statexe2x80x9d) as in the case where the lamp is used practically. The reason is that an arc bending phenomenon, i.e. a phenomenon in which an emission center is shifted slightly depending on the orientation of the lamp 1 when it is turned on, occurs in the lamp 1.
However, in such a conventional lamp with a reflector, since the lamp 1 is fixed to the hole 39 simply with the adhesive 22b, the adhesive strength between the lamp 1 and the adhesive 22 is lost when strong force is added to the base 2 in thread fastening of the nut 2b to the threaded portion 2a or the like. As a result, the lamp 1 cannot be fixed inside the reflector 40, which has been a problem.
When the lamp 1 is fixed to the reflector 40, a process for drying the adhesive 22 is required and the process takes a long time of at least 30 minutes. This also has been a problem.
Furthermore, there have been the following problems. Since the drying process is carried out by batch processing, it is difficult to obtain the consistency with a mass production line, thus complicating the manufacturing processes. In addition, when the mass-production volume is increased, the size of the drying furnace equipment is increased.
Moreover, in the horizontal turn-on state in adjusting the position of the lamp 1, the adhesive 22b moves to one side or flows out due to gravity. Therefore, after the lamp 1 is fixed inside the reflector 40 temporarily by drying a part of the adhesive 22b for temporal fixation, the reflector 40 is set again in a direction in which the adhesive 22b does not flow out and then the adhesive 22b is dried for finishing. Since such two drying steps are required, the process is complicated, which also has been a problem.
In addition, there also has been a possible problem of causing defects due to the accidental adherence of the adhesive 22b onto the reflecting surface 7 or the like when the hole 39 is filled with the adhesive 22.
The present invention aims to solve such problems. It is an object of the present invention to provide a lamp with a reflector in which a lamp can be fixed firmly inside a reflector by fixing the lamp inside the reflector without using an adhesive.
It also is an object of the present invention to provide a method of manufacturing a lamp with a reflector in which the position of a lamp can be adjusted easily inside a reflector by fixing the lamp inside the reflector without using an adhesive, no process for drying an adhesive and no equipment for the process are required, and further the occurrence of defects caused by adhesion of an adhesive can be prevented.
The lamp with a reflector of the present invention includes a lamp having a base at one end and a reflector. The reflector has, at one end of its reflecting surface, a hole into which the base of the lamp is inserted and an opening portion at the other end. The base is maintained in the hole, so that the lamp is positioned inside the reflector. A hollow metal fitting is fit into the hole, the base is inserted into the metal fitting, and the base and the metal fitting are combined into one component by welding. According to this configuration, the lamp can be fixed firmly inside the reflector without using an adhesive.
In the above-mentioned configuration, when the base and the metal fitting are welded at their boundary portion, they can be welded easily and reliably.
Preferably, the metal fitting has at least one slit formed by being cut from an end on the opposite side to the opening portion and has a flexible tongue portion that is formed by the slit. According to this, the tongue portion is deformed elastically and therefore the lamp can be tilted easily in any direction, thus facilitating the position adjustment of the lamp inside the reflector. Further, by providing the hole with a projection or a rib that is engaged with the slit, the length of the metal fitting to be inserted into the hole can be controlled, and when the metal fitting has a cylindrical shape, the rotation in the circumferential direction can be suppressed further securely. In addition, by providing a projection on the side face of the metal fitting and bringing the projection into contact with the inner face of the hole, the metal fitting is allowed to be fit tightly in the hole. Preferably, the above-mentioned slit is formed to extend to the vicinity of the end positioned on the reflector side.
When the hole has a tapered shape with the side of the opening portion of the reflector being wider and the metal fitting is inserted into the hole, the tongue portion is deformed to have its tip closer, thus deforming the metal fitting into a tapered shape. Therefore, the contact force between the base and the tongue portion increases when the base is inserted. In addition, the base seeks to press and expand the tongue portion and therefore the further intimate contact between the metal fitting and the hole also is attained.
It is preferable that a stopper to be caught by the end of the hole on the opening portion side is provided at one end of the metal fitting on the opening portion side. This can prevent the metal fitting from being inserted into the hole beyond a predetermined length.
Besides the above-mentioned slit, by providing the metal fitting with at least one slit formed by being cut from its end of the opening portion side, the difference in thermal expansion between the reflector and the metal fitting is absorbed, thus preventing damages.
Further, when a projection formed of a part of a spherical body is provided on the side face of the base and a top part of the projection is brought into contact with the inner face of the metal fitting, a constant sliding frictional force between the base and the inner face of the metal fitting can be obtained, thus facilitating the position adjustment of the lamp.
The manufacturing method according to the present invention is one for manufacturing a lamp with a reflector including a lamp having a base at one end and a reflector. The reflector has, at one end of its reflecting surface, a hole into which the base of the lamp is inserted and at the other end, an opening portion. The base is maintained in the hole, so that the lamp is positioned inside the reflector. The method is characterized in that a hollow metal fitting is fit into the hole, the base is inserted into the metal fitting, and then the base and the metal fitting are combined into one component by welding. According to this configuration, the lamp can be fixed firmly inside the reflector in a short time and the occurrence of defects caused by adhesion of an adhesive onto the reflecting surface also can be prevented.